Automatic alarm-bell



(No Model;)

B. P. FORBES.

AUTOMATIC ALARM BELL.-

No. 331,697. 'Pate'nted Dec. 1, 1885.

UwTTnn STATES PATENT Crrrcn.

EDXVARD P. FORBES, OF HARTFORD, CONNECTICUT.

AUTOMATIC ALARM=BELL SPECIFICATION forming part of Letters Patent No. 331,697, dated December 1, 1885.

Application filed June 25, 1885.

To all whom it may concern.-

Be it known that I, Enwiinn I. Forums, of Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Automatic Alarm- Bells, of which the following is a description, reference being had to the accompanying drawings, where- Figure l is a view of the upper side of one of my improved bells, shown in position on the edge of a door, the latter being in dotted outline. Fig. 2 is a top or plan view of the base-plate with the bell removed and the several parts in the same position as in Fig. 1. Fig. 3 is a view in cross-section through the device on plane denoted by line a: a; of Fig. 1, and looking toward the left. Fig. dis a detail view of the device with parts adapted to be fastened to a window. Fig. 5 is a detail plan view of the base-plate with the bell removed, illustrating the operation of the stop device.

The object of my invention is to provide an alarm-bell that can be removably attached to doors, windows, drawers, and the like in such position that the bell will be sounded whenever those several parts are opened, the device being automatically set in readiness for striking by the act of closing the door, window, or drawer.

My invent-ion consists in a base-plate with means for attaching it to a door or the like object, and supporting a beli, and the automatic striking mechanism, as more particu larly hereinafter described.

In the accompanying drawings, the letter a denotes a base-plate made of thin metal cut or cast to shape; a, a flange projecting from one edge of the plate at about right angles to the latter and bearing spurs a turned backward about parallel to the plate, the flange and spurs being so arranged that the base-plate will lie close against the inner edge of the door with the spurs on the flange embedded in the edge of the door next thejamb.

The letter 1) denotes agongbell, which is secured to a stump or standard, 0, that rises from about the center of the base-plate, and the hammer d is borne on the free end of the curved spring-tongue e, the other end of which is fastened to the baseplate. A rocksha-ft, f, is borne in hearings on the baseplate with Serial No. 169,707. (No model.)

a crank-arnnf, that extends beyond the baseplate, and is held at an angle with it by means of a spiral spring, 1, one end of which is fast to the shaft,while the other thrusts against the plate. The rock-shaft also bears a projecting trip-arm,f'-, so arranged as to alternately engage and release the arm 6 on the endof the spring-tongue e, and the downward motion of the crankarm f islimited by the stop 72., which is fast to the base-plate in such position that the trip-arm strikes upon it and prevents a further rotation of the shaft.

The arm 6 of the spring-tongue e, which bears the hammer, is supported in its normal position by the rest '6, fast to the base-plate, and when the device is set, as by the closing of the door, this arm lies above and upon the rest, and in front of and just below the trip, so that when the door is opened the springfrotat-es the shaft, so that the trip forces back the arm e until it slips off from it and releases the arm, and allows the hammer to strike against the bell by means of the recoil of the elastic tongue. By closing thedoor the rounded face of the crank-arm strikes against the jamb when the door is nearly closed, and as the closing continues the shaft is turned until the triparm is raised and slipped under the arm 6, and the device thus automatically reset.

The above description of my device illustrates its method of use when applied to a door; but it is equally applicable, with slight modifications of the crank-arm and setting mechanism, to windows and drawers, the device being set by the closing of either of these parts, and operated by opening them.

I11Fig. iof the drawings the deviceis shown with the form of arm adapted for use on a window, the base-plate being fastened to the sash by means of screws or nails driven through holes in the base-plate, and the arm projecting from the base-plate far enough to strike a pin or stud driven into the side of the window in the path of the crankarni as the sash is raised and lowered. The striking and setting mechanism is the same in this bell as the one already described.

In order to prevent the bell from striking each time the door is opened and closed, the stop j is used, and this may consist of the arm pivoted to the plate, and arranged to swing in the plane of the plate, so as to hold the crankarm of the rock-shaft and prevent it from turning as the door is opened; or it may consist of the spring-arm j, attached at one end to the standard and extending radially outward passing under the elastic tongue, and so arranged that when it is pulled to one side and engaged back of the lug 75 on the plate it will hold the tongue up so that the arm e will be clear of the trip device.

I claim as my invention 1. In combination, a baseplate,with a bell supported on the plate, an elastic tongue bearing the hammer, and a rock-shaftjournaled in bearings on the plate and having a crank-arm and a trip-arm, the latter alternately engaging and releasing the bell-tongue as the shaft is rocked, all substantially as described.

2. In combination, a base-plate, a, with the flange to, having spurs a the bell b, elastic tongue 0, bearing the hammer, the spring-act uated rock-shaft, with the crank'arm and triparm, and the stop h, all substantially as described.

3. In combination, a base-plate,with a bell supported on the plate, an elastic tongue bearthe bell-tongue as the shaft is rocked, all substantially as described.

4. In combination, a base-platemith a bell supported on the plate, the elastic tongue bearing the hammer d, the tonguerest 13, the rockshaftf, with the crank-arm f and trip-armf the spring g, actuating the rook-shaft, and the stop h in the path of the trip-arm f, all substantially as described.

5. In combination, a baseplatemith a' bell supported on the plate, an elastic tongue hearing the hammer, a rock-shaft journaled in bearings on the plate and bearinga crank-arm and a trip-arm, a tripping-spring adapted to rotate the rock-shaft, the trip-arm projecting so as to alternately engage and release the belltongue as the shaft is rocked, and the catch j, all substantially as described.

EDWARD P. FORBES.

Witnesses:

H. R. WILLIAMS, A. G. TANNER. 

